Acoustical device



Aug; 21, 192s.

J. J. KUHN ACOUSTIGAL DEVICE Filed June 24. 1919 Patented Aug. 21, 1928.

' JOHN J KUHN, OR ELrZABRTrL'NEw JERSEY, A s'srGNoR ro WESTERN ELEcTRrc COM- RANY, INOORRORATRD, OR NRW YORK, N. Y.,.AOORPORAT1ONOR NRWv YORK.

Acou's'rioAL nav-ICE.

' Appiicatioa aied Jane 24,

' rThis invention relates to acoustical devices and more particularly to devices of this character employed in the bin'aural method of observing and locating sources of ,vibrations n such methods, it isthe usualr practice to introduce an independent. air path between each oit a pair ot', relatively fixeddevices :tor converting the vibrations into observable effects, and tlieiespective ears 4of theA observer. 'By vthe proper relative ad; A justinent of the lengths of thetwoair paths, the diterence in time of Varrival at each of .the affected devices of vibrations propagated from the source under observation may be c :ompensated Vfor so that a binaural balance may be obtained, or in othery words, the observer receives the impression that thesource f is directly ahead when .listening binaurally to the observable ellects.- The angular' Vrejlation of the sourcetoabase 'line lioiniiig thevibration responsive Ymembers of theicon- .verting Adevices Vmay then be determined from: anV indicating means associated Vwith the compensator which designates thefrel'a.n

paths.

In order that accurate observations may be made following this method, it is `desirf able Ythat the air vpathsfof thercompensating f device shall. be acoustically insulated ,'"from eachother to prevent intererenCe'COmmOnly called crosstalk between the Yobservable'etf ects'simultaneou'sly passing over such paths.

- It is the lobject of'k this invention` to provvide V'an improved compensating `device of i this character in .f which linterference'between' the observable eilectvs'in the variableflength' air tubes `is prevented.`

, To attain `thisobject in accordancewith a eature of theinvention,l the air paths ota.

Y compensator employed for this purpose are completely surrounded by Vinetallic walls,

i .thereby eliminating the possibility ot" any anda sectional view of a device. embodying Y the invention, while Figs. 3 and 4 show sec-. v

' interchange through'- an'` air medium of the observa-ble effectsiii vthe paths;

This and other features of the invention not speciiicallymentioned above willclearlyA appear from the following specification, andV l. the annexed drawing, Figs. 1.and'2of which show a top plan view partially section tional views of portions of lsuch devicetaken along the lines anda-#10i Figs. 1 and,l

. ploy'ed ford etermining`-` the direction of a 2, the portions shown in section. Fig. being` taken along the 'lines llof Figs.

2,13 and t, 5 showsk diagiamniatically'the manner in'which the device isemsource of vibration.

@In the drawings, a` supporting framework of asuitable table topl, omitted from l* ig. 1 forthe sake of clearness, by Ameans of Vwhich'in'aybe suitably securedto the under l1 screwspassing through holes 3 Vin a plurality lugs 4 is providedV with avc'rtical slot '8,

anintu'rned portion of whichengages one' end of a bent bracket 9,3the other end 'of 10 by means o t' screws 11. 1 A shaft "12 passes through' the Journal Yportion 6 ofthe supporting framework and an aligned Clearanceective lengthsv oi the ad]ustabl e airV4 .table top l1' and'prov'ided with a knob or liandle'QB." The lower plate member 13 is rigidly' securedfto-` the shaft 12"byv 'a pin 14 passingthrough theferruleQ of the plate 14 and engaging the shaft 12. Immediately which is' suitably attached to a body member above the body member v1() an upper plate "member, 15 is rigidly' secured to the shaft 12 by means fof'a key 1(5 eiigaging suitable coopf ei'ati1ig keywaysfin la terruie '17 of the platelfand theshaftl. "The upper sur- Y face of the; joui1ia l portion' 6 is provided vwith 'ja lower bearing plate 18 suitably at- 'tached theretdand cooperating withy balle.

bearings 19 introduced between such bearing plate' andfan upperv bearing plate 20 suitably attached to the lower surta-ee' of a bushing member 21,rigidly' attached'to the Yshaft 12 by means 'otfa 9111.22 and to' which the screws 2 4. A xedly positioned,stop-'meinmember cooperateswith the movable stop pins 26 and 27 fsuitably attached at predetermined separated locations to upper plate direction of 'such' plate member and'of-.the 'simultaneously rotating lower plate member' 25 upwardly extending vtrom thebent 1 i 'i member 15 toi limitl theA rotation inv either i A lephonefeceiyer v2e Secure/alte .thev

' loA r .emplee understandin upper'pl'ate 'member 15`by rigid tube 29 projectingr fromV the easing* thereof-and-v Vthre'adec'lly engaging, a iho'le 3,0 throngh'fth'e upper plate'member v15, '.Ausimilar receiver 31 is attached to the lower platemember 13 by a rigid tube 32-threadedlyengaginig -ahole 33 through the lowerplate 'member"1 3 These receivers arenotshovvn'infdetail since Y' their exact .structure is 'non essen t ial {toa fof the .inventlom -i 'ordinary enclosed reeeiverfbeing inV theQciajsings that tliey convey the sounds produce'dfby" the receivers in respon'seft-o" variations in the electrical"conditions of as'- sociat'ect circuits', Countervveights tand 35,

' [suitablyattachedfto the upper'plate `n 'iernber 1.5; uid 'l'w'er platenmeiiber -134 reSptively, 'arefprovided to' balancerthe Weights of" the v V: issocatjed receivers 28 and 31' respectively,

thereby insuringfree nflliaiifrmrotation of the, 'platey members and niaintaii'iing the v surfaces of SuQh'plate'members in' proper' Contact relationwvith the', cooperating surfaces.v of thebody member-'310.

v 'The upper surface of thefbody member, 10 u is provide'dvgi'tlra concentric circular groove 36 preferablyoffa semi-circular cross-sect1om The insertmember 3T, the'upper surface Voi y the upper surface the a .iiishl-'Inouted insert member secured to -fthefbody irember in fa ,-"ositon directly eral edge of the body;membefr.v B

aperte@ 43 in' the .by meliibf 10.,.19eted near the relativelyoppos'ite side of menfiberA 41 extendsromtheZgroovefO' to ,the peripht i Y ber, :provide attachments orf eqalxlength tubes and 47 preferably"'ofgrubbenf lead-i" ving 'toiusual stethosc'opic' earpieces '48 and 49. Closelyiadjacent'one Vside thehole'30 f Y A member 54 attachedto'fthebu through fthe' upper#plate.y member 1 5, a -lug relatively opposite side 'ofl the holefi33f a Shi-ngel' byA screwsf 55 rotates `with fthe shaft 12, and- Amay,

' ,--befprpvidei with suitably graduatedseule observable rthroughl the :aperture 56 in the;

rvtable' t p 1,'indicating the degree 'of rotation elbow-shapedr 0f the eine undef the 'Simuimpegesiy mming plates Y1'3/and115." The arrangement of Y invention;

The operation of the device maybe more -c.learly---1i.nderstoocl by reference to the diagram of conne ctions, as shown on VFig. 5, rom w'vhrch -itW-lll'be 'seen that the sounds produced by- Y receiver 28,., f are vconveyed .from above, *through aW portion'of'the 'groove to vdetermine the effective -1 -length Vthe #suc-h s caleshas been omitted since'it is unessentiel lt0 Ve idear understandzmgf Qfqzthe voperating bushing 41 andE the tube'tf-to the "ear piece 48, Vlug 5O=Vand insert 37 cooperating ,e

groove. The sounds producedbythereceiver" 31 are 'similarly conveyed through the rigid tubel in ka clockwise direct-ion*'throughf-a portion of the ygroove 40, the elbowshaped passao'e VWay 43,' the-"cooperating bushing 545,

eifective length' of the groove.` f Thl observer, listening binaurally sounds emanating* from V the ear l pieces48 andy .49 simultaneously'receives rthe vSounds produced bythe receivers; Thehan'dleis then rotated until the'i-mpression 'is-ref:

ceivedthat the source' of sound isstraight ahead and area-'dingen the" portionV` of the between the Y'receivers' and thev respective ears 15 what asrhefdisence thrugh fheigrobve scale;l vof member* ilaeiiposed through the opening' in ,the'tabletop 11,"indc'a-ting the relativel lengths of thej'afir-paths V'irrite'rp'osed between one lugf-andi the cooperating'bu'sh'ing Y incre'asesgg'theisimilar distance 'between theV other flug Vvand `"the cooperating 'bushing 'decreases al corresponding amount. 'In ilthis manner, Vthe c liffere'nce in V"distances 1f-rom ja source of vibration 1to1-thefvibrationrespon-v `Y I and 45, threadedly Y e'ngagin lthebody niem- A operating circuitsffofreceivers 28 and@ 31,-f respectively 'meyfbe compensated: 0r binnuVr rally' balanceo?by[corresponding` diierences the observer receives the impressionfthat ,the source of sound is s',tralghtgahead.r

'l lDue. Ito, Ifnetallie?v valls completelysurpensator, Ythe .possibilityo'f' the' 'transference errorsfin observation introduced thereby. A i

iso

portion, channels formed on the opposite sides thereof, means to close the opensides thereof and means sliding in such channels to vary the effective lengths thereof.- y

; 2'. In an acoustical device, a framework, a'shaft rotatably supported thereby, a body Amember rigidly supported by the framework and having a circular groove in-"each of two surfaces, a plate member carried the shaft in close relation to each such surface .Y of the body member, means rendering each circular groove discontinuous, and a lug attached to each platemember slidably engag-` ing the groove of the cooperatingsurface.of`

the body member, said lugs cooperating with jthe above mentioned means for inversely varying the lengths. of portions ofthe Vgrooves interposed therebetween.

3. InV an acoustical device, a framework,

a body member rigidly supported :thereby and `having a concentric circularV groove 1n each of two surfaces thereof, means Afor rendering Leach groove discontinuous., an outlet v e member 'acoustically connected with each groove, a'shaftv rotatablyV supported by the 'K framework, aplate memberV supported by the shaft and inA contact relationwith yeach Y'such surface of the bodyfmemb'er, a sound producing device attached to each, plate member and acoustically'v connected to the 'Y groove in the-adjacent surface of the body member, a stop member attached to each plate member adjacent the sound producing device and slidably engaging the groove in the contacting'surface of the body member,

said stop members simultaneously causing an inverse and equal variationin the effec-f tivelengthsofthejgrooves fromy the sound l producing devices to the outletmembers during-the rotationy ofthe shaft, and means carried by each plateY cooperating with `the associated sound producing device to main-r tain the contact relation' Vbetween the plate members and the associated surfaces of the body member.

4. In an.acoustical body member rigidly supported thereby and having a concentric` circular groove in each` of two surfaces thereof, a stop member in! s'erted'in each such surfacev to render each groove discontinuous, a stethoscopic tube acoustically .connected to each groove through. the body portion, said tubes being located onvrelatively opposite sidesv of the associated stop members, a shaft rotatably supported by the framework, afplate lmember carriedv by the shaft and in Contact rela- Ytion wit-heach surface ofthe body member,

a stop member carried by each plate and slidably engaging the groove in the contact,-y ing surface of the body portion, and a` sound producing device acoustically' J connected Awith eachV groove through the contacting ofthe grooves interposedbetween the sound. j. i 70v producing devices' and the stethoscopic tubes. Y

device, a framework, a

' In witness whereof, I- hereunto subscribe Y my name this 18th day of June, A. D., 1919. y s w i `JOHN J. KUHN. 

